The present invention relates generally to land vehicles operable by a rider in a non-upright position and more specifically to recumbent pedalable vehicles.
Pedalable land vehicles such as conventional bicycles operated by a rider in an upright position are well known. Other versions of pedalable vehicles have also been reported wherein the rider operates the vehicle in a non-upright position. See, generally, Gross, et al., Scientific American 249/6:142-152 (December, 1983).
Of interest to the present invention are the following reports of pedalable vehicles wherein the rider is seated in a reclining or "recumbent" position: Turner, et al., U.S. Pat. No. 4,333,664; Hopkins, et al., U.S. Pat. No. 4,279,429; Hopkins, U.S. Pat. No. 4,198,072; Matsuura, U.S. Pat. No. 3,921,467; and Robinson, U.S. Pat. No. 3,753,577. Turner, et al. discloses a recumbent bicycle wherein the rider is seated in a reclining position and operates pedals located at the front end of the frame and steers the vehicle by moving a handlebar integrally attached to the front wheel. The bicycle frame comprises small diameter tube supports which support the crank assembly, front and rear wheels, bicycle seat and the bicycle chain drive interconnecting the crank assembly and rear wheel which chain drive runs along the exterior of the frame. The seat disclosed in Turner, et al. is a padded fiberglass shell supported by an intricate seat back support system to prevent torsion during pedaling. The Hopkins U.S. Pat No. 4,198,072 discloses a tricycle recumbent vehicle having a bicycle chain drive assembly located alongside the front portion of the frame interconnecting the crank assembly with the front wheel and a rear two-wheel steering carriage assembly allowing pivoting of the rear axle about two different axes. The seat 15 is provided in two sections, a hip support section and a back support section joined at a pivot allowing angular positioning of the back support, and is integral with the frame. Hopkins U.S. Pat. No. 4,279,429 discloses a tricycle-type recumbent vehicle having a steering control mechanism including hand grips integrally attached to the rear axle and a gimbal means that provides pivotal steering movement of the rear wheels about two axes. The tricycle has a bicycle chain drive located alongside the front portion of the frame interconnecting the front wheel with the crank assembly and a seat provided in two portions, a hip support portion and a back support portion. Matsuura U.S. Pat. No. 3,921,467 discloses a recumbent cycle chain drive assembly located along the longitudinal axis of the cycle. The disclosed tricycle recumbent vehicle drive chain includes a primary sprocket attached to the cycle pedal assembly and a final sprocket attached to the rear wheels' axle and tensioner sprockets therebetween which route the cycle chain below the cycle seat in the center of the open tricycle frame to attempt to prevent entanglement of the rider. The disclosed cycle drive also includes a partial chain guard located over part of the crank assembly sprocket and drive chain. Robinson U.S. Pat. No. 3,753,577 discloses a recumbent tricycle pedalable vehicle having the seat attached to the frame between the rear wheels and at a height below that of the rear wheels' axles. The steering assembly comprises a handlebar assembly connected to a sprocket interconnected by a chain to a sprocket connected to the front wheel. A dual chain drive assembly attached alongside the frame having two chains interconnecting a pedal assembly sprocket with the rear axle sprocket is also shown.
Also of interest to the present invention are reports of attempts to provide more efficient and aerodynamic pedalable vehicles. See, generally, Gross, et al. "The Aerodynamics of Human-Powered Land Vehicles", Scientific American Vol. 249, No. 6 (December, 1983) pp. 142-152. Reported vehicles therein included several varieties of recumbent bicycles (p. 148) having chain drive assemblies located alongside tubular frame structures. Steering assemblies employed include handlebars attached directly to the front wheel (Easy Racer, Schondorf All-Weather Vehicle) and handlebars mounted below the rider's seat (Avatar 2000). The Avatar handlebars are interconnected with the front fork by a tie rod attached to each handlebar and the front fork. Similar versions of aerodynamically designed recumbent vehicles have been reported by the International Human Powered Vehicle Association in its September, 1983 report of the Ninth Annual Human Powered Speed Championships. Included in the reported vehicles is the "Infinity" recumbent bicycle having a bicycle chain drive located alongside the tubular frame and a steering assembly including a handlebar assembly welded to rear portion of the frame at a fixed position and interconnected with the front wheel fork assembly by two cables, one cable interconnecting the left handlebar with the left side of the front fork and a right cable connecting the right handlebar with the right side of the front fork. The seat is welded to a slide attached to the rear of the frame near the point at which the handlebars are fixed to the frame and has two parallel side supports supporting a fabric hammock-type seat.
Of particular interest to the present invention is the fact that the reported recumbent bicycles all have chain drive asemblies located alongside the vehicle frame in close proximity to the rider's legs resulting in significant risk of entanglement of the rider with the chain. The reported recumbent vehicles have also been found to be difficult to maneuver at low speeds due to the limited turning capacity provided by the steering assemblies reported which do not provide more than about a 45.degree. turn of the steering wheel to either side.
There exists, therefore, a need in the art for safer, more maneuverable recumbent vehicles adapted to readily accommodate a variety of different size riders.